I noticed the change in the reputation titles, but I just figured the titles were moved back in terms of how much rep was required for them. I didn't know a whole new system was made . o . nice work.
I remember that girl in Snowpoint City who'd trade you a Haunter for a Medicham...and the Haunter had an Everstone!
It's more possible to "catch them all" in some fangames than it is in the official games.
Akora Forest is reached from Surfing east of Akuwa Town through Route 11. Mankey are in the trees, and you need a Chestnut for them to notice you. A girl in the forest gives you one, and there some laying around the forest too.
I'm 100% sure (out of 101%) that it's just Greninja mimicking Ash, but if they did give Greninja a mega, I would hope they also give one to Chesnaught and Delphox.
I actually read an article about it not long ago.
Someone met Junichi Masuda and asked him about it. He said they didn't put anything like that in the game, so the interviewer showed it to him. He just said "Oooooo" a few times and smiled.